The present invention relates to a high molecular sensor and manufacturing method thereof in which polypyrrole which is a conductive high molecule is electrochemically polymerized and then reduced and thereby ionic conductivity is given so that humidity sensibility is made to be excellent.
High molecule having conjugated structure exhibits an electric conductivity essentially by doping, to which polyacetylene, polyparaphenylene, polyaniline, polyacene, polypyrrole, polythiophene, and polyfuran are included. These conductive high molecules are used for pH sensor, pressure sensor, sulphuric acid concentration sensor, oxygen and bionic sensor, and glucose sensor and the like. And, there are example used for alcohol and gas sensor as well as humidity sensor. Among which high molecules used for humidity sensor (Japanese laid-open patent publication No. 88-133050, 88-122758, 85-201244) were polyfuran, polythiophene, polyphyrrole, and heterocyclic compound of their derivatives, and wherein it was simple structure used with glass coated with indium tin oxide (ITO) for electrode of sensor, and separate reducing process for improving ionic conductivity was not executed. In such case, since there is limitation in humidity sensing speed and humidity measuring region, post-process for improving the precisely made sensor structure and ionic conductivity is required.
Polypyrrole, polythiophene, polyfuran and the like which are a kind of heterocyclic compound are electrochemically polymerized, at the same time a doping occurs to thereby exhibit electric conductivity. Therefore, the electric conductive mechanism may be said that electronic conduction and ionic conduction are operated in complex, and since the ionic conductivity produced at non-crystalloid within high molecule is weaker than electronic conductivity, it can be said that it is a conductivity by almost electronic conductivity.